Manipulating the composition of absorbent polymers affects product and by-product concentration profiles in the biphasic biotransformation of indene to cis-1,2-indandiol

The biotransformation of indene to the pharmaceutical intermediate, 1,2-indandiol, by Pseudomonas putida 421-5 (ATCC 55687) produces large amounts of the inhibitory by-product, 1-indenol, as well as several different minor degradation products. Three segmented block copolymers, Hytrel® 8206, Hytrel® 3078, and Pebax® 2533, containing varying types and amounts of soft segment components, exhibited different affinity toward the product and by-product. The polymers were each used as the sequestering phase for metabolite removal from this transformation in a two-phase partitioning bioreactor (TPPB). The polymer with the highest affinity for each metabolite enhanced its production via more extensive partitioning into the polymer phase. This work reports the first use of polymers whose differing compositions are attributed to target molecule affinity and the different production profiles seen during two-phase biocatalysis. The uniquely high water content of 30 wt% in Hytrel® 8206 emphasized the importance of accounting for water uptake in partition calculations, and potentially conferred enhanced affinity and diffusivity by providing an expanded polymer network, significantly improving biotransformation completion time compared to the low-water-absorbing polymers.